In liquid conduit systems, it is often important that gasses are removed from the liquid in the conduit system. These gasses generally occur as free gasses or absorbed by the liquid. This is in particular important in conduits for heating systems, but may also be important in other situations. For this purpose, gas removal devices have been developed.
Further, it is often desired that dirt parts are removed from the liquid inside the conduit system. These dirt parts may come loose from the inner walls of the conduits. Due to the flow of the liquid inside the conduit system, the dirt particles may be held in suspension.
If these dirt parts are not removed, they may clog up the conduit system or damage certain components in the conduit system, such as pumps.
Also, particles of other liquids may contaminate the main liquid in a conduit system. The contaminating liquid may be lighter or heavier than the main liquid.
In the prior art, it is known to use a separate gas removal device and dirt removal device. However, this is relatively costly and not very practical.
A combined gas removal and dirt removal device is known from WO97/10037. This device has a gas removal element and a quiet zone below the gas removal element. In the quiet zone, dirt should come to rest and settle on the bottom.
A problem associated with the device of WO97/10037 is that e dirt removal function does not work very well. The liquid does not become calm enough to allow dirt parts or particles from a heavy contaminating liquid to settle.
In the conduit system, the liquid has a substantial speed. This speed needs to be substantially reduced in the quiet zone, in order to allow the dirt parts or particles from a heavy contaminating liquid to settle. It is in particular difficult to remove the smaller particles under 50 microns from the liquid. Another requirement is that a substantial discharge should be directed through the quiet zone, because otherwise the part of the flow which is cleaned is too small to affect the dirt level or level of particles from a heavy contaminating liquid in the total flow.
It was found that the device of WO97/10037 does not succeed enough in reducing the velocity of the liquid at any acceptable resistance of flow. The dirt parts or particles from a heavy contaminating liquid are substantially held in suspension and do not settle to the bottom of the quiet zone. Furthermore, the flow of the liquid remains substantially turbulent, i.e. variable in time, which further contributes to the dirt particles or particles from a heavy contaminating liquid being held in suspension.
A possible solution could be to substantially increase the size of the quiet zone. However, in practice a device of limited size is desired in the field, for cost reasons and also because devices of limited size are more practical during installation. A substantial increase in the size of the apparatus would lead to an apparatus of impractical size.
DE4017229 further discloses a device for removing contaminations from liquids in a liquid conduit system. The device of DE4017229 also does not provide satisfactory results. Rather than to settle to the bottom, the dirt tends to be conveyed with the main flow through the device. The gas bubble also tend to be conveyed through the device, rather than to be removed. The device according to DE4017229 is also quite large, which is not very practical in many situations.